In a typical electronics manufacturing process, circuitry including, but not limited to, printed circuit boards, flexible substrates, packages such as multichip modules (MCM), etc. may be populated with electronic devices using pick-and-place operations. For example, the circuitry may be routed through machines equipped with vision systems for identifying device placement locations in the circuitry and manipulators configured to pick up devices from a supply location (e.g., rail, reel, etc.) and place the devices into the previously identified device locations. Pick-and-place manufacturing has been effective at least from the standpoint of accurately populating circuitry with a variety of devices at a speed substantially faster than manual device insertion.
However, applications are now emerging wherein circuitry may need to be populated with high volumes of the same device. For example, recent developments in light emitting diode (LED) technology have created substantial demand for LED-based light sources due to their high quality light, low power consumption and long life. Manufacturing large-scale LED lighting (e.g., for commercial or professional use) may involve populating circuitry with thousands of the same LED. While pick-n-place manufacturing can do the job, high machine time and upkeep costs, limited production speed, etc. for performing such simple/repetitive assembly can be prohibitive.
Electronic manufacturing methods better suited for high volume production are now in development. For example, fluidic self-assembly (FSA) is a manufacturing method that relies upon the wetting behavior of liquids (e.g., solder) to populate circuitry. For example, electronic components (e.g., LED die) may be assembled by drawing a circuit substrate through an agitated liquid bath. The liquid bath may be heated above the melting point of solder that has been pre-printed on the circuit board. Due to the agitation, bond pads on the components may randomly contact the molten solder on the circuit substrate, at which point the solder provides enough wetting and lubrication for the components to naturally find their device locations (e.g., their minimum energy configuration). In particular, the wetting effect of the melted solder may cause conductive pads or bumps on the devices to be drawn to conductive pads in the device locations. While FSA may provide a method by which circuitry may be populated with a large number of devices, at least one issue still exists in regard to device orientation in the circuitry. Currently no effective provisions exist to control the orientation of devices being populated into the circuitry. For example, existing control measures require custom devices and/or circuitry to mechanically steer device orientation, which may be prohibitive due to substantially increased material costs.
Although the following Detailed Description will proceed with reference being made to illustrative embodiments, many alternatives, modifications and variations thereof will be apparent to those skilled in the art.